Subfertility, defined as delayed time-to-conception, affects an estimated 12% of women of reproductive age. The use of fertility-enhancing therapies, including assisted reproductive technologies (ART), has risen steadily in the United States due to several factors, including childbearing at older maternal ages and increasing insurance coverage. Prior studies of women's and children's health after ART have been limited by small sample sizes, non-US populations, or ART treatments performed more than a decade ago, and the lack of appropriate control groups. An important understudied area is that of non-ART fertility treatments and the perinatal, infant, and child health outcomes of these pregnancies. Our original pair of grants was the first population-based analysis of women's and children's health after ART to be conducted in the US. These studies, which had the unique strength of including a non-ART-treated subfertility comparison group, yielded a series of analyses suggesting that underlying subfertility, rather than the treatment modality, is the foundation for most maternal and child morbidity. In this renewal, we will expand this understanding through increased information on subfertility-related diagnoses, underlying non-subfertility medical conditions, non-ART treatment parameters, and outcome measures present in the All Payers Claims Database, as well as inclusion of new information on fathers. We will evaluate the health of mothers during pregnancy and for five years post-delivery, and their children through age four. The study population will include all Massachusetts women who delivered pregnancies between 2004 and 2011 (our original birth cohort) and their children, and will add study subjects who delivered between 2012 and 2017. The total study population will include more than one million families. Reference groups will include ART and non-ART pregnancies with only male factor infertility, and pregnancies without indicators or treatment of subfertility. The study aims and hypotheses are: Aim 1: To evaluate the effect of maternal subfertility diagnoses on long-term health; Hypothesis: Women with a history of subfertility diagnoses, independent of treatment, have higher risks of compromised health outcomes compared to women without indicators or treatment of subfertility; Aim 2: To evaluate the health of children born to women and men with subfertility diagnoses; Hypothesis: Children born to women and/or men with subfertility diagnoses, independent of treatment, have a higher risk of compromised health outcomes compared to children born to women without indicators of subfertility; and Aim 3: To develop a cost-of-subfertility measure for women and their children; Hypothesis: Women with a history of subfertility-related diagnoses and their children have higher healthcare costs compared to their counterparts without indicators or treatment of subfertility.